Luminous Landscape Forum

Raw & Post Processing, Printing => Digital Image Processing => Topic started by: Fine_Art on January 19, 2013, 05:03:30 PM

Title: Noise reduction by channel
Post by: Fine_Art on January 19, 2013, 05:03:30 PM
I have tested a new method (as far as I know) for Noise Reduction. Unless I hear its published already I will call it Arthur's method.  ;)

Here is a link from Sony A99 @6400 as published in RAW by Imaging Resource. All rights to the RAW are theirs. I have done a conversion using NR by RGBL channel.
http://fs02n2.sendspace.com/dl/a9f06e0a4aedbad8c9510ed701cd51d6/50fb12b408dba234/cibx6j/CVT_AA99hSLI06400NR0%20NR%20Curves.jpg (http://fs02n2.sendspace.com/dl/a9f06e0a4aedbad8c9510ed701cd51d6/50fb12b408dba234/cibx6j/CVT_AA99hSLI06400NR0%20NR%20Curves.jpg)

This file has a lot less noise than their jpg version. Basically the idea is to treat each of the 4 channels as a 3 dimensional space for Noise Reduction. If you end up with mild patterns like the attached conversion you can break the original into CMYL do noise reduction on each channel then save. Combine both results in layers or by math operation average.

Your noise reduction software running on a powerful computer is far more capable than a simple de-bayer routine. The raw converters available are very good on low ISO. They seem to produce a lot more noise than this method on high ISO files. I did my work in ImagesPlus, a scientific imaging program

I am not in the imaging business so I am not going to try to develop this somehow. Anyone can use it. If someone puts it in their blog, book, document, whatever, I expect it to be called Arthur's method referencing Lula and Dyxum. I worked on it for a couple days posting on LuLa and Dyxum as FineArt.

People can easily verify that the method works.

A99 ISO6400 @ 50% attached.


Title: Re: Noise reduction by channel
Post by: bill t. on January 19, 2013, 05:29:43 PM
That link is to an .exe file.  No way.  Could you please just post a full sized crop or something?
Title: Re: Noise reduction by channel
Post by: Fine_Art on January 19, 2013, 06:46:49 PM
That link is to an .exe file.  No way.  Could you please just post a full sized crop or something?

Sendspace is pushing their toolbar and ads. Ignore that and look at the link lower center in the blue box. If you hover your mouse over it it wall show a .jpg file.

Edit: For those that dont have bandwidth here is a screenshot of the RED channel seperated. Left is high ISO before NR. Right is the same file after NR. This is repeated for RGB and L channels. All channels have channel specific noise.


Title: Re: Noise reduction by channel
Post by: Tim Lookingbill on January 19, 2013, 10:15:27 PM
Quote
I am not in the imaging business so I am not going to try to develop this somehow. Anyone can use it. If someone puts it in their blog, book, document, whatever, I expect it to be called Arthur's method referencing Lula and Dyxum. I worked on it for a couple days posting on LuLa and Dyxum as FineArt.

I wouldn't worry about anyone giving you credit for your method, I doubt anyone's going to use it anyway.

Too much work for what little results it brings using such an obscure piece of software. Besides you haven't posted any instructions on how to do it EFFICIENTLY so photographers can apply it to the multitude of shots they have to process.

And BTW, don't know if you're aware of this but your noise reduction sample shots you've been posting have random glitter like white dots throughout the image. It's almost has a crystalline effect. Weird.
Title: Re: Noise reduction by channel
Post by: Tim Lookingbill on January 19, 2013, 10:35:15 PM
Just took a shot of my display showing the jpeg you posted on your original response which shows the spots up close. The B&W red channel sample you posted doesn't have this, but other similar RGB composite shots your've posted in other threads on the subject show the spots as well.
Title: Re: Noise reduction by channel
Post by: Fine_Art on January 20, 2013, 03:10:11 AM
Just took a shot of my display showing the jpeg you posted on your original response which shows the spots up close. The B&W red channel sample you posted doesn't have this, but other similar RGB composite shots your've posted in other threads on the subject show the spots as well.

I cant see much past the screen door effect of your LCD. Just reference the post if you want more info.

This?
(http://www.luminous-landscape.com/forum/index.php?action=dlattach;topic=74133.0;attach=73344;image)
Title: Re: Noise reduction by channel
Post by: thierrylegros396 on January 20, 2013, 03:54:22 AM
Impressive results !

As already said, it seems to produce a lot of small bright dots.

But I imagine these are easier to remove than lower frequency dots.

Thanks for sharing.

Thierry
Title: Re: Noise reduction by channel
Post by: stamper on January 20, 2013, 04:22:01 AM
If my ageing memory is correct then Dan Margulis has pioneered these methods in one of his books. I will have a look later to confirm this. It is very doubtful if you were the first. I would take a step back and think before making any more doubtful claims. :(
Title: Re: Noise reduction by channel
Post by: stamper on January 20, 2013, 06:12:31 AM
Quote Fine_ Art.

I have tested a new method (as far as I know) for Noise Reduction. Unless I hear its published already I will call it Arthur's method.

Unquote.

Dan Margulis covers noise reduction in channels in his Professional Photoshop book 1st Edition and in his book Photoshop LAB Color. He recommends a trip to the lab colorspace and blurring the A and B channels and then going back to RGB, It is well known that the blue channel is the noisiest and this method reduces it. Sharpening in the blue channel is not recommended. I don't think Arthur's method is a new concept?
Title: Re: Noise reduction by channel
Post by: thierrylegros396 on January 20, 2013, 10:40:44 AM
But perhaps your method is more effective.

So we stay tuned to see how you do in detail !

Thierry
Title: Re: Noise reduction by channel
Post by: BartvanderWolf on January 20, 2013, 11:37:00 AM
I don't think Arthur's method is a new concept?

Not necessarily, but it's completely different from what Dan Margulis was preaching. Dan is suggesting the blurring of the Chroma channels, while Arthur is focusing on removing noise at the Raw stage before demosaicing (which normally would turn single pixel noise into multiple pixel blobs of color). That's what Astrophotography tends to do, improve the signal to noise ratio as much as possible before demosaicing.

The challenge is in reducing the noise (not only chromatic noise), but not affect the capability to demosaic actual resolution at the same time.

Raw converters like DxO Optics Pro, RawTherapee 4.x, and Capture One Pro 7, offer noise reduction and Luminance detail control that works at the Raw data level, while being Color Managed. The program Arthur uses (ImagesPlus) is not color managed, and also a bit too specialized for regular photographic use. Some of the noise reduction functions of ImagesPlus are adaptive (edge preserving), and can be tweaked at the Bayer CFA level, before the demosaicing, and before leaving the linear gamma space.

A very high quality (and Color Managed !) alternative for ImagesPlus, is PixInsight (http://www.pixinsight.com/). However, that's also not very easy to use, mainly because it's documentation is not available for many of the functions (although a lot can be learned from their forum members), and it is more than just an image processing application. It's also a program development environment for image processing, mainly focusing at the needs of astronomers, but it is very well programmed by a small team of dedicated programmers/astronomers.
 
Cheers,
Bart
Title: Re: Noise reduction by channel
Post by: Fine_Art on January 20, 2013, 12:58:41 PM
Quote Fine_ Art.

I have tested a new method (as far as I know) for Noise Reduction. Unless I hear its published already I will call it Arthur's method.

Unquote.

Dan Margulis covers noise reduction in channels in his Professional Photoshop book 1st Edition and in his book Photoshop LAB Color. He recommends a trip to the lab colorspace and blurring the A and B channels and then going back to RGB, It is well known that the blue channel is the noisiest and this method reduces it. Sharpening in the blue channel is not recommended. I don't think Arthur's method is a new concept?

Ok thanks. I will have to get his book.

Forget "Arthur's method" call it "Dan's method"! I just re-invented the wheel.
Title: Re: Noise reduction by channel
Post by: Fine_Art on January 20, 2013, 01:42:56 PM
Not necessarily, but it's completely different from what Dan Margulis was preaching. Dan is suggesting the blurring of the Chroma channels, while Arthur is focusing on removing noise at the Raw stage before demosaicing (which normally would turn single pixel noise into multiple pixel blobs of color). That's what Astrophotography tends to do, improve the signal to noise ratio as much as possible before demosaicing.

The challenge is in reducing the noise (not only chromatic noise), but not affect the capability to demosaic actual resolution at the same time.

Raw converters like DxO Optics Pro, RawTherapee 4.x, and Capture One Pro 7, offer noise reduction and Luminance detail control that works at the Raw data level, while being Color Managed. The program Arthur uses (ImagesPlus) is not color managed, and also a bit too specialized for regular photographic use. Some of the noise reduction functions of ImagesPlus are adaptive (edge preserving), and can be tweaked at the Bayer CFA level, before the demosaicing, and before leaving the linear gamma space.

A very high quality (and Color Managed !) alternative for ImagesPlus, is PixInsight (http://www.pixinsight.com/). However, that's also not very easy to use, mainly because it's documentation is not available for many of the functions (although a lot can be learned from their forum members), and it is more than just an image processing application. It's also a program development environment for image processing, mainly focusing at the needs of astronomers, but it is very well programmed by a small team of dedicated programmers/astronomers.
 
Cheers,
Bart

It's a bit different, not quite what Dan did, from your explanation and not quite what you describe. I must have failed to communicate it properly.

This method does not really let me remove noise before de-mosaicing. I am doing my steps after de-mosaicing. What I guess my method shows is that the de-bayer algorithms are nowhere near as advanced as the latest de-noise algorithms. I am also using them in different dimensions. Thinking this way is more natural to someone who has matrix math training and/or someone who has OLAP database training. It's more of a jump for others. It can still be done.

I am using the power of a modern computer with modern noise reduction in 12 dimensions. In camera processing cannot touch this. For example my software is 64bit multi-threaded on a quad core 2.8 GHz with 8 Gigs RAM. Forget tiny chips in your camera for JPGs.

What we assume our de-bayer method does is fill in holes from missing pixels on each color to re-create full image by color layer just as the old film color layers did. I would say for Low ISO whatever they are doing seems to work. The problem comes to High ISO when we see very harsh jumps in pixel values (noise) or wandering color patterns. Clumps of colors without NR. This is a processing failure not necessarily a shot S/N problem.

So here it is again. My process uses the best NR programs on each color channel. I happen to use Images Plus for a very clean (random) noise conversion. I'm sure other programs like what Bart mentions work well too. The TEST for working well is leaving a fine random pattern of noise. There should be no clumps of color. When you seperate out the channels you should still see fine random noise that looks like fine film grain.

Attached is a screenshot of Blue, Green and Red channels shown in B/W. The noise is strongest on Red, then Blue, then Green. Your favorite N/R programs noise ninja, topaz de-noise, neat image, whatever will do wonders on this. Use it on RGBL. The noise also looks the same in CMYL. Do it again. Re-combine each split RGBL, CMYL. Combine both in layers or using average functions.

What you have done is take slices through a 12 dimension matrix, wiped out pixel to pixel variances in each dimension, leaving a very natural looking file with real depth. Heavy NR as your raw converter programs do it leave a very artificial looking image. With their methods your choice is leave noise in or look artificial.

So by Bart's description Dan's method is not the same as Arthur's method. The name Arthur's method stays.

Title: Re: Noise reduction by channel
Post by: Fine_Art on January 20, 2013, 01:56:34 PM
Looking at that screenshot in the prior post, it is easy to understand that smoothing functions will create smooth waves from those fine speckles. That is what most converter software is doing. When re-combined those waves will not line up. Areas that randomly have slightly higher values in 3x3, 5x5 or 9x9 for example will be different coordinates on each channel. Recombining those leads to lumps of color. You see artificial patterns of wandering red, green, blue. Clearly that was not in the real world. Clearly it was not at the bayer level which is single pixel level noise. It is from smoothed waves that are out of phase by channel.

If your software does this it is failing you. Use something else.
Title: Re: Noise reduction by channel
Post by: opgr on January 20, 2013, 02:33:43 PM
This method does not really let me remove noise before de-mosaicing. I am doing my steps after de-mosaicing. What I guess my method shows is that the de-bayer algorithms are nowhere near as advanced as the latest de-noise algorithms.

You're still not making sense and contradicting yourself.

Bayer data gives you only one of R, G, or B for each pixel, and you therefore need to come up with a value for the other two channels per pixel. Applying noise-reduction prior to this stage and/or after this stage, on difference-signals of any kind is the standard method of denoise. You are currently deluding yourself (and others) by making it a feindishly complex combination of everything and then claiming nonsense about RAW converters and dedicated DSPs.

A dedicated denoise program will have more parameters to control noise reduction because the RAW converter generally makes compromises for the sake of speed. The most effective additional parameters in dedicated noise-reduction are the separation of the blur radius per difference level. Any which way you turn it, the general method is to take some kind of average to determine what constitutes noise and what constitutes signal. This average signal is what causes the large blobs of color. It is the average signal. It is not some kind of crap that the RAW converter is introducing. If you would look at a live-view of the image, these blobs would move even though the actual image would be stationary.

A dedicated noise-reduction program will have several levels of average signal and perhaps even colorprofiles for strength etc. You could keep the noise at the pixel level, and remove it at the larger average levels. That would give you your preferred fine-grained colornoise. LR 4 seems to have introduced new pyramid levels for the image processing which also allows both more sophisticated noise reduction as well as local contrast control which also works with these difference levels.

I think the only thing you are currently doing is using a really round-about way of saying that modern noise-reduction programs and algorithms do a better job than what is available in most RAW converters. Well, that is exactly why there are dedicated software options. What you should define is what it is exactly that you expect from the RAW converter to feed into the denoise-software. Simple interpolation like nearest-neighbor or linear?

Additionally, if you think yourself well-versed in matrix math, then you should know that you can matrix-convert an RGB triplet all day long, into as many dimensions as you like, but that ain't gonna do sh*t for the RGB triplets on the output side. If it can be described in matrix form, then it isn't doing anything. It is the additional math that introduce non-linearities and averaging that is making the difference.








Title: Re: Noise reduction by channel
Post by: Fine_Art on January 20, 2013, 03:04:17 PM
You're still not making sense and contradicting yourself.

Bayer data gives you only one of R, G, or B for each pixel, and you therefore need to come up with a value for the other two channels per pixel. Applying noise-reduction prior to this stage and/or after this stage, on difference-signals of any kind is the standard method of denoise. You are currently deluding yourself (and others) by making it a feindishly complex combination of everything and then claiming nonsense about RAW converters and dedicated DSPs.

A dedicated denoise program will have more parameters to control noise reduction because the RAW converter generally makes compromises for the sake of speed. The most effective additional parameters in dedicated noise-reduction are the separation of the blur radius per difference level. Any which way you turn it, the general method is to take some kind of average to determine what constitutes noise and what constitutes signal. This average signal is what causes the large blobs of color. It is the average signal. It is not some kind of crap that the RAW converter is introducing. If you would look at a live-view of the image, these blobs would move even though the actual image would be stationary.

A dedicated noise-reduction program will have several levels of average signal and perhaps even colorprofiles for strength etc. You could keep the noise at the pixel level, and remove it at the larger average levels. That would give you your preferred fine-grained colornoise. LR 4 seems to have introduced new pyramid levels for the image processing which also allows both more sophisticated noise reduction as well as local contrast control which also works with these difference levels.

I think the only thing you are currently doing is using a really round-about way of saying that modern noise-reduction programs and algorithms do a better job than what is available in most RAW converters. Well, that is exactly why there are dedicated software options. What you should define is what it is exactly that you expect from the RAW converter to feed into the denoise-software. Simple interpolation like nearest-neighbor or linear?

Additionally, if you think yourself well-versed in matrix math, then you should know that you can matrix-convert an RGB triplet all day long, into as many dimensions as you like, but that ain't gonna do sh*t for the RGB triplets on the output side. If it can be described in matrix form, then it isn't doing anything. It is the additional math that introduce non-linearities and averaging that is making the difference.


Modern NR programs do not use averaging. Images plus has several NR functions that do not smear out edges or fine detail.

You can blab all you want about how it cant work. Anyone who does it on their computer picking the best NR by channel they can find, will see a big jump in image quality.
Title: Re: Noise reduction by channel
Post by: Tim Lookingbill on January 20, 2013, 03:32:18 PM
I cant see much past the screen door effect of your LCD. Just reference the post if you want more info.

This?

Yes, those tiny white specs. What causes that and can it be fixed?

The test shot you posted of the proportion wheel is very impressive with regard to detail as seen in the proportion wheel, but I don't see your methods attaining these results as functional for regular photographers seeing we aren't matrix mathematicians.

I'm assuming you've already shown this to photo astronomers, but I'm trying to understand why you'ld think regular photographers would find any use in this. Or maybe you're just wanting to toot you're own horn at finding a better mousetrap and if that's the case you might consider contacting competing Raw converter vendors of your newly discovered method and sell it to them.

I'm not familiar with the photo astronomy community, but I'm guessing that they're very highly technical individuals who can examine the math behind what you're doing and figure it out for themselves. Also I can't believe they'ld be resorting to CFA Bayer methods of recording the cosmos and manipulating data like this to support the idea that what they're photographing is actually factual and expecting us to believe it knowing those methods employed. I thought photo astronomy would be using a lot more sophisticated technology rather than simple bayer sensors and software interpretation.
Title: Re: Noise reduction by channel
Post by: Fine_Art on January 20, 2013, 03:32:47 PM
Nikon D800 ISO3200 NR0 converted in Images plus. Note the fine random nature of the noise.

The second screenshot is with NR by channel. It gets some faint color grouping from the NR. The noise does not start to form into a pattern.

Title: Re: Noise reduction by channel
Post by: Tim Lookingbill on January 20, 2013, 03:41:40 PM
I would think the forensic video recovery investigators of law enforement who have to make out license plates and facial features within noisy crime scene video would be interested in your methods if it could be applied in the same manner.
Title: Re: Noise reduction by channel
Post by: Fine_Art on January 20, 2013, 03:48:57 PM
I would think the forensic video recovery investigators of law enforement who have to make out license plates and facial features within noisy crime scene video would be interested in your methods if it could be applied in the same manner.

They widely use deconvolution sharpening technology. So would the military on their recon imaging. Do they use NR by channel? Probably not, most of their work is B/W for the higher sensitivity of no color filters.
Title: Re: Noise reduction by channel
Post by: Tim Lookingbill on January 20, 2013, 04:17:50 PM
They widely use deconvolution sharpening technology. So would the military on their recon imaging. Do they use NR by channel? Probably not, most of their work is B/W for the higher sensitivity of no color filters.

So I take it from your answer that means no, it wouldn't be feasible for that type of application. So what use do you see this method widely adopted?

I noticed no one else in this thread posted their own NR method to compare against. It seems most of the functionality lies in your skill set, Arthur. I know I wouldn't be able to pull those results off with my own 6MP Pentax PEFs.
Title: Re: Noise reduction by channel
Post by: Fine_Art on January 20, 2013, 06:33:53 PM
So I take it from your answer that means no, it wouldn't be feasible for that type of application. So what use do you see this method widely adopted?

I noticed no one else in this thread posted their own NR method to compare against. It seems most of the functionality lies in your skill set, Arthur. I know I wouldn't be able to pull those results off with my own 6MP Pentax PEFs.

The functions are in the software I named. All someone has to do is run them on their image. People that try to use this method from software that creates color clumps are going to have problems. The data needs to be as fine as possible.
Title: Re: Noise reduction by channel
Post by: Fine_Art on January 20, 2013, 08:36:48 PM
What works on high ISO with noise reduction works at low ISO for Sharpening.

Here is Images Plus sharpened by channel using Adaptive Richardson-Lucy on the left
Sony's IDC which makes a very good image on the right. IDC was my default converter, I know how to squeeze quality out of it very well. I used to send tiffs from it to Images Plus for sharpening.

Look at how natural the left file looks compared to the right file. In addition problems like red fringing were wiped out. This is huge. I always hated looking at files at 100% because they looked fake. Yes, I tried samples of Capture one, DxO, ACR and Raw Therapee for comparisons in the past. At 50% view Sony IDC was as good. The color was better, the detail was a bit less. Still easy to solve with AR-L.

On low ISO files the room for channel sharpening is huge. Artifacts don't build up easily.
Title: Re: Noise reduction by channel
Post by: bjanes on January 21, 2013, 01:06:31 PM
Nikon D800 ISO3200 NR0 converted in Images plus. Note the fine random nature of the noise.

The second screenshot is with NR by channel. It gets some faint color grouping from the NR. The noise does not start to form into a pattern.

IMHO ACR with Noiseware for noise reduction provides equivalent or better results than your method and with more convenience and with color management, which your images from ImagesPlus lack. I note that your uploaded image is untagged. The colors are only generic. For most of us, color management and accurate colors are highly desirable.

With the D800, I find that NR is often unnecessary with even high ISO if one uses proper technique. Your test image is underexposed by over 1 stop as shown by Rawdigger.

Nonetheless, one often must make best use of what one has. I rendered the image into sRGB with ACR 7.3 and then applied some NR with Noiseware (I haven't felt the need to use Noiseware for some time, but it is a good plug in to have). Your conversion is on the top and there is still some speckling in the top wrapper of the wine bottle. Also the print on the calculator shows some edge artifacting and fuzziness. For my routine photography I will continue to use ACR/LR. Depending on the ISO and print size, NR beyond what is offered by LR/ACR is usually not needed with the D800. The sophisticated filters and other image processing functions in ImagesPlus are sometimes useful, but I would render the image into a TIFF with defined color space with ACR and then load the image into ImagesPlus. I think this is what Roger Clark does.

Regards,

Bill
Title: Re: Noise reduction by channel
Post by: Fine_Art on January 21, 2013, 03:43:15 PM
IMHO ACR with Noiseware for noise reduction provides equivalent or better results than your method and with more convenience and with color management, which your images from ImagesPlus lack. I note that your uploaded image is untagged. The colors are only generic. For most of us, color management and accurate colors are highly desirable.

With the D800, I find that NR is often unnecessary with even high ISO if one uses proper technique. Your test image is underexposed by over 1 stop as shown by Rawdigger.

Nonetheless, one often must make best use of what one has. I rendered the image into sRGB with ACR 7.3 and then applied some NR with Noiseware (I haven't felt the need to use Noiseware for some time, but it is a good plug in to have). Your conversion is on the top and there is still some speckling in the top wrapper of the wine bottle. Also the print on the calculator shows some edge artifacting and fuzziness. For my routine photography I will continue to use ACR/LR. Depending on the ISO and print size, NR beyond what is offered by LR/ACR is usually not needed with the D800. The sophisticated filters and other image processing functions in ImagesPlus are sometimes useful, but I would render the image into a TIFF with defined color space with ACR and then load the image into ImagesPlus. I think this is what Roger Clark does.

Regards,

Bill

To each their own. I think the detail looks better in mine.

Images Plus does not preserve exif.
Title: Re: Noise reduction by channel
Post by: Fine_Art on January 21, 2013, 03:47:25 PM
Maybe someone with DxO testing software or imatest can compare the results.
Title: Re: Noise reduction by channel
Post by: bjanes on January 21, 2013, 05:04:23 PM
Maybe someone with DxO testing software or imatest can compare the results.

I have Imatest, but problems arise since the rendered file from ImagesPlus is untagged. When you open the converted file in Photoshop you get a warning that the file is untagged as to color space. You can leave color managed or assign a profile. This is covered in this post (http://www.earthboundlight.com/phototips/untagged-rgb.html).

I have a Nikon D3 image of a colorchecker photographed under Solux illumination (approx 4800K). I rendered the image with ImagesPlus and to gamma 2.2 and saved it untagged. I then opened it and assigned sRGB, Adobe RGB, and ProPhotoRGB. The results are shown along with  an ACR conversion. The color errors in the ImagesPlus conversions are very large. This proves my point.

Regards,

Bill
Title: Re: Noise reduction by channel
Post by: Fine_Art on January 21, 2013, 05:25:49 PM
Thanks, that is certainly a real issue.

What are your thoughts on the detail of the image you posted? On mine the texture of the metal wrapper on the bottle is clearly visible. On yours it is smeared out looking flat. On the background the noise is basically random on mine, on yours it is forming into color clumps. What is your analysis of that?
Title: Re: Noise reduction by channel
Post by: bjanes on January 21, 2013, 06:04:04 PM
Thanks, that is certainly a real issue.

What are your thoughts on the detail of the image you posted? On mine the texture of the metal wrapper on the bottle is clearly visible. On yours it is smeared out looking flat. On the background the noise is basically random on mine, on yours it is forming into color clumps. What is your analysis of that?

I think that the wrapper in your image exhibits speckled artifacts that have been pointed out previously and the printing shows artifacts as I noted. Both of us are not unbiased observers, and others may comment. I am satisfied with my results and you like yours, so we are both happy.

Regards,

Bill
Title: Re: Noise reduction by channel
Post by: Schewe on January 21, 2013, 06:35:49 PM
I have tested a new method (as far as I know) for Noise Reduction. Unless I hear its published already I will call it Arthur's method.  ;)

Not for nothing but I'm pretty sure Bruce Fraser wrote about per channel sharpening and noise reduction back in one of his early Real World Photoshop books well over a decade ago. Doing per channel noise reduction offers more flexibility than when running on composite RGB data. If you look at the Reduce Noise filter in Photoshop (with the advanced option checked) you'll see that the amount of the noise reduction can be adjusted on a per channel basis. As I recall, both Reduce Noise and Smart Sharpen (which also has per channel options) have been around for a long time and as I recall, Bruce was involved in early alpha testing of both with the engineers.

But if you are working with raw images (as apposed to film scans) I have a feeling that the ACR/LR noise reduction is pretty much leading edge and has made 3rd party noise reduction (or obscure image processing routines) a bit passe. Not reason not to keep experimenting but it's useful to know that work being done now is often (not always) built on the work of others...
Title: Re: Noise reduction by channel
Post by: Fine_Art on January 21, 2013, 08:13:19 PM
Not for nothing but I'm pretty sure Bruce Fraser wrote about per channel sharpening and noise reduction back in one of his early Real World Photoshop books well over a decade ago. Doing per channel noise reduction offers more flexibility than when running on composite RGB data. If you look at the Reduce Noise filter in Photoshop (with the advanced option checked) you'll see that the amount of the noise reduction can be adjusted on a per channel basis. As I recall, both Reduce Noise and Smart Sharpen (which also has per channel options) have been around for a long time and as I recall, Bruce was involved in early alpha testing of both with the engineers.

But if you are working with raw images (as apposed to film scans) I have a feeling that the ACR/LR noise reduction is pretty much leading edge and has made 3rd party noise reduction (or obscure image processing routines) a bit passe. Not reason not to keep experimenting but it's useful to know that work being done now is often (not always) built on the work of others...

Thanks for the info. I'm a property developer that went to top business schools not someone in the photoshop community. I knew if it was out there someone would bring it to my attention. Per channel NR/ sharpening in whatever software does seem to be the way to go.

I seem to remember when I originally looked at the new lightroom it was $299 or something. The new $99 does make it an easy purchase for testing. Right now I think I will stay with Sony IDC, Raw Therapee and Images plus. I like the smoothing/ sharpening functions in IPlus. The flexibility of no default gamma correction is also useful.

Snow detail in a 1 of 3 shot pano. There was noise in that sky before.
http://farm9.staticflickr.com/8471/8404208734_1e82308404_o.jpg (http://farm9.staticflickr.com/8471/8404208734_1e82308404_o.jpg)
Title: Re: Noise reduction by channel
Post by: Fine_Art on January 21, 2013, 08:52:44 PM
I posted at Dyxum that this was done by Bruce Fraser many years back. I'm making sure credit goes back to him.
Title: Re: Noise reduction by channel
Post by: Tim Lookingbill on January 21, 2013, 09:51:30 PM
Quote
I'm a property developer that went to top business schools not someone in the photoshop community.

Has that helped you or hindered you in your endeavors here in getting your point across?

You didn't happen to develop the neighborhood of Fairhaven in Schertz, Texas, did you? We need better developers down here in Texas who know how to build decent foundations on top of loose limestone rubble bedrock.

If you're good, get down here. The Eagle Ford Shale gas and oil production site needs a lot of homes built fast and good for all the new oilfield employees.
Title: Re: Noise reduction by channel
Post by: bjanes on January 22, 2013, 04:29:50 PM
But if you are working with raw images (as apposed to film scans) I have a feeling that the ACR/LR noise reduction is pretty much leading edge and has made 3rd party noise reduction (or obscure image processing routines) a bit passe. Not reason not to keep experimenting but it's useful to know that work being done now is often (not always) built on the work of others...

With the OP's test image, I think that the default ACR settings do a reasonable job of noise reduction while maintaining edge contrast and fine detail. The default color settings remove almost all of the color noise and the residual luminance noise is fine grained and acceptable with the default of no luminance noise reduction. Had the image been properly exposed to the right, I think the image would have been even better. I do have Noiseware, but rarely use it with the D800e. Viewing a 36 MP image at 100% is a severe test, and the noise might not be visible in ordinary prints.

Regards,

Bill
Title: Re: Noise reduction by channel
Post by: Fine_Art on January 22, 2013, 06:10:21 PM
Most of the credit has to go to Nikon and Sony for one hell of a camera and one hell of a sensor. With everything turned off, that test shot, despite being underexposed at ISO 3200 looks like what you would expect from ISO 400 on APS-C cameras or ISO 800 on FF of just a few years ago. Frankly the cleanup task for software was not that bad.

The ACR/LR version looks pretty good with an artificial black peppering. Color noise is controlled in the last version posted. Some fine detail is lost despite lines looking sharp. Its visible on the textured metallic wrapper.

The process I used, I'll call it Bruce's per channel NR kept fine detail by using other algorithms. The white pixels I created with deconvolution are less frequent than the black pixels of ACR. Neither will likely show up in a print. If you don't like the white ones, just run fewer cycles of deconvolution or move the slider for noise threshold. I had it at 5 standard deviations on a range of 0-10.

Attached is a screenshot of some of the smoothing and sharpening functions in Images Plus. It's a tightly coded 64bit multi-threaded app that is only 7.5MB in size. The entire installation is 8.82MB for the 4.25 version. That is pretty amazing. No code bloat here. A lot of this capability is not available in other software.

I have no association with Mike or the software other than a happy user. I get no other benefit than using it.
Title: Re: Noise reduction by channel
Post by: bjanes on January 22, 2013, 08:25:19 PM
Attached is a screenshot of some of the smoothing and sharpening functions in Images Plus. It's a tightly coded 64bit multi-threaded app that is only 7.5MB in size. The entire installation is 8.82MB for the 4.25 version. That is pretty amazing. No code bloat here. A lot of this capability is not available in other software.
I have no association with Mike or the software other than a happy user. I get no other benefit than using it.

Your approach is interesting and would be useful when noise reduction in ACR/LR is not sufficient. The parametric editing in LR is attractive because the 36 MP D800 file expands to 200 MP in a 16 bit TIFF. How do you determine the PSF for deconvolution?

Regards,

Bill


Title: Re: Noise reduction by channel
Post by: Fine_Art on January 22, 2013, 08:57:11 PM
Your approach is interesting and would be useful when noise reduction in ACR/LR is not sufficient. The parametric editing in LR is attractive because the 36 MP D800 file expands to 200 MP in a 16 bit TIFF. How do you determine the PSF for deconvolution?

Regards,

Bill




In the screen shot above the deconvolution controls are the top right and bottom left boxes. The top right has 3 types, Van Cittert, One step Gradient (VC with a mild smoothing in between each cycle) and Richardson-Lucy. The bottom left is all Adaptive R-L. Adaptive R-L like Adaptive USM engage only areas that meet defined parameters. These are superior to the standard versions in other software.

The PSF for all methods is defined by size (3x3, 5x5, 7x7,9x9) and type Gaussian (most common) Binomial, Box and Custom. The custom controls are lower right. You can enter values or select from the image with the mouse. If you select you can scale the values.

An example of the use of custom would be to reverse lens defects. If you take a picture of the night sky you have point sources with atmosphere effects and lens effects. You would probably deconvolve with Gaussian. If you take a picture of an artificial star or points without miles of atmosphere to contend with the errors are from your lens only. If you right click on the deformed point the custom box fills with the values of that selection. Center it. Deconvolve the image. You should get back to a point without diffraction rings. Save that "custom" for use with that lens. If you want your rings you can enter them from calculation around the central value and save that.

If you have a lens with shitty smearing in the corners you could use this process then apply it to the corners with the rest of the image masked out.

Drooling yet?
Title: Re: Noise reduction by channel
Post by: Fine_Art on January 25, 2013, 01:28:10 AM
Crop from a single frame of tonight's moon ISO400. N/R and sharpened using this method.

Title: Re: Noise reduction by channel
Post by: jerryrock on January 25, 2013, 10:40:22 AM
How does this method compare with noise reduction features present in ACR 7.3 combined with the per channel noise reduction available in Photoshop CS6?
Title: Re: Noise reduction by channel
Post by: Fine_Art on January 25, 2013, 01:59:34 PM
Bob showed a comparison. I'm sure he is a very skilled user of ACR.
Title: Re: Noise reduction by channel
Post by: Fine_Art on February 05, 2013, 02:15:02 PM
Here is my conversion of Imaging Resource Nikon D800 ISO 3200 NR0
http://www.flickr.com/photos/fineart48/8447544957/sizes/o/in/photostream/ (http://www.flickr.com/photos/fineart48/8447544957/sizes/o/in/photostream/)

The full size image will be available until the end of March when flickr ends its free Christmas gift.

Download the nef, compare your own conversion in C1, DxO, LR, Photoshop (in case I didn't answer your PS question with ACR).

Bob's LR version a few posts up is covered in black pepper. Was that in the original scene? No, its an artifact that increases perceived sharpness.

My version has a faint random color noise still in it. It is so light it is not objectionable from ISO3200.
Title: Re: Noise reduction by channel
Post by: Fine_Art on March 14, 2013, 11:55:19 PM
This is now implemented in RT 4.0.10.1 You can take your pick of RGB or LAB

Very cool.